Method and means for translating electrical impulses into mechanical force



March 25, 1947. w. M. WINSLOW 2,417,850

METHOD AND MEANS FOR TRANSLATING ELECTRICAL IMPULSES INTO MECHANICALFORCE Filed April 14, 1942 7J g 4 y INVENTIOR l V/L 4/5 M. VV/NSLOW.

/%i ATTORNEY.

Patented 25, i947 ZAllflSt METHOD AND MEANS FOR TRANSLATING ELECTRICALHVIPULSES INTO LIECHANI- CAL FORCE 22 Claims.

This invention relates to a method and means for transmitting amechanical movement or force in response to an electrical potential. 1

The principal object of the invention is to provide a device of thischaracter which will operate on exceedingly slight currents withoutamplification being necessary and without the use of electromagnets.

The invention comprises what might be termed an electro-fluid clutch.While it has been de scribed as particularly applied to the operation ofa relay for closing a second circuit in response to an electricalvoltage or impulse received over a first circuit it is not, of course,limited to this particular application. It will be found useful whereverit is desired to cause a moving drive member to transmit movement to adriven member in response to very slight electrical currents arisingfrom any source.

In actual practice relays controlling heavy electrical loads have beencontrolled by currents of such slight intensity as to be immeasurable bythe usual instruments such as currents arising from photo-electric cellcircuits or electro-static charges, either uni-directional oralternating at any frequency.

Other objects and advantages reside in the detail construction of theinvention,. which is designed for simplicity, economy, and efliciency.These will become more apparent from the following description. v

In the following detaileddescription of the invention reference is hadto the accompanying drawing which forms a part hereof. Like numeralsrefer to like parts in all views of the drawing and throughout thedescription.

In the drawing:

Figs. 1 and 2 are diagrams illustrating the basic principle of theinvention;

Fig. 3 is a top view of a photo-cell relay constructed to employ theprinciple of the invention;

Fig. 4 is a side view of the relay of Fig. 3;

Fig. 5 is a vertical section through the operating element of theimproved relay; and

Fig. 6 is a fragmentary, detail view of the contacts of the improvedrelay.

This invention contemplates the use of what IiS believed to be a novelphenomenon of electricity. I have found that if two plates are separatedby certain substantially dielectric fluids containing certain substancesthe fluid mixture will tend to cause the two plates to act as a unit aslong as an electrical potential difference exists between the plates.

This principle may be experimentally demonstrated, as shown in Fig. 1 inwhich, apower drive shaft III is provided with a disc II and a drivenshaft I2 is provided with a disc I3. The two discs are maintained inclosely spaced, parallel relation and are insulated from each other bymeans of a suitable dielectric or substantially dielectric fluid mixtureI4 held between them by capillary attraction. The two shafts are in anelectrical circuit I5 containing any source of electrical energy I6 andany suitable circuit closing device II. Electrical potential is appliedto discs I I and I3 by means of the closing device I'I. Since the fluidI4 is substantially dielectric, very little current will flow throughthe circuit.

While the circuit is open there is no noticeable tendency for the discI3 to rotate with the rotating disc I I but when the circuit I5 isclosed at II, the disc I3 immediately rotates with the disc II as a unitwith considerable force and persistence. The instant the circuit isopened the driven disc I3 stops and the drive disc I I continues torotate.

Many fluid mixtures have been found to accomplish this result with moreor less efficient results. It appears that the fluid must be adielectric, or substantially non-conducting at all operating electricalpressures, for very little current flows through the fluid between theplates.

Therefore, a low viscosity, non-conducting liquid is preferred as thefluid medium. Fluids which have been found suitable are light weighttransformer oil and transformer insulating fluids such as pyranol,inerteen, etc., olive oil, mineral oil, etc. A pure fluid or a pure oilalone, however, does not act to tie the plates together under theinfluence of the electric current to any practical extent. However, whenan additional substance, in the nature of a finely divided material, isadded thereto the tying effect is very pronounced. Such substances asstarch, lime stone, or its derivatives, gypsum, flour, gelatine, carbon,etc. all create the desired effect with more or less efficient results.It is probable that some fluid and/or some additional agent which arestill untried will give even better results than any so far experimentedwith. To date, the applicant finds that a pharmaceutical mixture ofrefined mineral oil and lanolin in which starch granules (approximately20% by volume) have been placed gives good results. It is believed thatthe resulting mixture is simply a mechanical one as there does notappear to be any chemical reaction between the elements of the mixture.

Just what takes place in the fluid when the electrical potential isimpressed upon the plates is not definitely known. It appears, however,from close observation of the mixture in action that there is a tendencyfor suspended particles, probably the starch, in the oil to form in aninfinite number of strings or lines extending between the plates whileunder the influence of the potential. These strings or lines immediatelydisappear when the circuit is broken. Perhaps these strings or linestend to, in a sense, tie the plates together or increase the sheetstresses between them by their tendency to prevent relative movement inthe strata of the fluid body.

Whatever be the full explanation, it is manifest that the viscosity ofthe fluid is greatly increased in the presence of the electrical fieldand a homogeneous fluent mechanical linkage, or coupling, is therebyestablished. This increase in viscosity takes place without a change intem perature.

The effect is clearly not the result of positive and negative electricalattraction of the plates since such attraction would operate only atright angles to the plates tending only to move them toward each other.Since the plates cannot move axially but are only free to rotate, nomovement can result from said electrical attraction. The effect can beattained with either direct or alternating currents of any frequency.There is no permanent change in the mixture as it instantly releases andregrips rapidly and indefinitely. Currents of such low values as arecarried by the hand of the experimenter without wires serve to cause thetwo plates to rotate in unison. The body of a person when moving hisfeet back and forth across a carpet will store an electrostatic chargesuflicient to operate the device. The slight current passed by theelectrons of a photoelectric cell from a series connected source ofsupply will also operate the device.

The effect can be put to many uses. for instance a relay structure suchas diagrammed in Fig. 2 may be based on the principle of this invention.This relay employes a drive shaft |8 driven from any source of motivepower. The shaft |8 supports a fluid cup l9. A driven disc 28 issuspended in the cup I 9 out of contact with the bottom thereof on adriven shaft 2|. The cup contains a dielectric fluid mixture 22 such aspreviously described. A relay blade 23 is secured to the driven shaft 2|and projects therefrom between a pair of relay contacts 24 and 25. Theblade 23 is constantly urged against the contact 25 by the action of aspring 26.

The direction of rotation of the cup 9 is such as to tend to swing theblade away from the contact 25 and against the contact 24. The contact24 may control any desired circuit devices such as lamps 21 and thecontact 25 may similarly control any desired circuit device such as asecond series of maps 28. Electrical voltage is impressed on the cup l9and on the plate 20 by the terminals of a control circuit 29 containinga source of electrical energy 30 and any suitable condition responsivecircuit closer such as a'photo-electric cell 3|.

Whenever a light beam strikes the cell 3|, an electrical potentialdifference is impressed on both the cup l9 and the plate 20 causing thefluid 22 therebetween to exert a clutching or tying effect between thetwo. This causes the plate 20 to rotate with the cup so as to swing therelay blade 23 from the contact 25 and against the contact 24, thusextinguishing the lamps 28 and lighting the lamps 21. When the lightceases to impinge on the cell 3| current ceases to be impressed on thecup and plate'and the clutching eiiect instantly ceases. The spring 26then draws the relay blade 23 back to the contact 25.

A practical construction for such a relay is illustrated in Figs. 3, 4,and 5, mounted on a suitable base block 32. The base supports asynchronous motor 33 of the telechron" type which drives a bevel pinion34 at slow speed through suitable reduction gears contained in a gearbox 35. A bevel gear 36 rests upon and is in constant mesh with thepinion 34.

The bevel geat 36 is formed on a fluid cup 31 having a downwardlyprojecting bearing post 38 which is rotaa'ably fitted over a pivot stud39. The stud 39 projects upwardly from a base flange 40. Thus it can beseen that operation of the motor will rotate the cup 31 at slow speed.The connections to the motor are usual and are therefore notillustrated.

The cup 31 contains a superimposed series of washer-like plates 4|separated by means of separating rings 42. The series of plates andrings are clamped together by means of a threaded, flanged cap 43 whichalso seals the top of the cup.

A shaft 44 is journalled in an insulating bushing 45 in the cap 43 andextends downward into the cup through the open centers of the plates 4|.This shaft carries a superimposed series of discs 46 separated byseparating sleeves 41, the upper one of which extends through thebushing 45 to a clamp nut 48. The entire series of discs and sleeves areclamped together as a unit by tightening the nut 48. The discs 46 andthe plates 4| do not contact but are maintained in close parallelrelation. The cup is substantially filled with a suitable substantiallydielectric mixture 56 of mineral oil and starch as above described andis free to revolve about the shaft 44 without imparting rotation to thelatter. The shaft 44 supports a relay arm 49 which is bifurcated at itsfree extremity and terminates between a pair of spaced relay contacts5|] and 5|. A spring 52 constantly urges the relay arm toward thecontact 5|.

The cup 31 is connected through the base flange 40 to the base of astandard photo-electric cell 53 through a conductor 56. The contact 50is connected to a binding post 55. The spring 52 is connected to asimilar binding post 51. The contacts 58 and 5| and the posts 54, 55,and 51 are supported on and insulated from a frame member 58.

Two electrical supply mains 59 and 58 lead to the relay. The main 59leads to the upper terminal of the photo-electric cell 53 and the main60 leads to the post 51. A first controlled circuit wire 6| is connectedto the binding post 55 and through any electric apparatus which it isdesired to control such as a lamp 62 to a return lead 63 connected withthe main 59. A second controlled circuit wire 64 is similarly connectedto the binding post 54 and to a lamp 65 which is also connected to thelead 63. While the photo-electric cell has been illustrated as mountedon the base 32, it could, of course, be mounted in any place convenientfor the use to which it is to be placed.

The synchronous motor 33 may operate continuously, since it is one ofthe small electric clock types and requires but very little current. Thespeed of the motor is reduced through the gears in the box 35 and thepinion 34 to slowly rotate the cup. In actual practice the cup wasrotated once in eight minutes with very satisfactory results.

Whenever a light beam strikes the photo-eleccell 55, a small electricpressure will be impressed upon the plates 4| and the opposed discs 46which creates the phenomenon in the fluid mixture of the cup previouslydescribed causing the discs to immediately rotate with the plates. Thisswings the relay arm 49 against the action of the spring 52 so that thecircuit 8| is broken at the contact i and the circuit 64 is closed atthe contact 5|]. As soon as the light beam ceases to strike thephoto-electric cell, the discs 46 are instantly released and the spring52 again acts to close the contact 51. The action of the fluid isinstantaneous and the gripping effect even with a current of the orderof a microampere has been suflicient to flex or bend the relay arm 49.

It is desired to call attention to the fact that the relay is operateddirect from the small current flow of the photo-electric cell. There isno amplification of the control current as is now necessary with theusual electro-magnetic relays.

The invention is adaptable to many uses, in fact to substantially alluses for which relay tubes or electro-magnets are now being used, suchas for controlling circuits, operating speakers and signal devices,clutching power shafts, etc. especially where very low current valuesare involved in the control circuits.

It will be noted that any desired delay in closing may be had by simplylowering the speed of rotation of the cup or varying the spacing betweenthe contacts 50 and 5|. The speed of release may be controlledelectrically through condensers and resistances arranged to provide adefinite time delay in the voltage drop of the control circuit.

The sensitivity of this relay is such that it can be operated in an openelectrical circuit, under conditions where, due to atmospheric charge,charge due to relative movements, or potential gradients of location,there is created a potential difference between the two electrodes orplates. Under such conditions simply short circuiting the plate elementswill restore the relay to initial position.

The term fluid mixture as used in this specification and in the appendedclaims is defined as a mixture, between a liquid or liquids and anothersubstance or substances suspended therein. The term dielectric as usedherein is defined as substantially dielectric that is, a relatively poorelectrical conductor such as an oil or the like.

While preferred forms of the invention have been described in somedetail together with the theories which it is believed best explain itssuccess, it is to be understood that the invention is not limited to theprecise procedures described nor is it dependent upon the accuracy ofthe theories which have been advanced. On the contrary, the invention isnot to be regarded as limited except in so far as such limitations areincluded within the terms of the accompanying claims in which it is theintention to claim all novelty inherent in the invention as broadly asis permissible in view of the prior art.

Having thus described the invention, what is claimed and desired securedby Letters Patent is:

1. A method for transmitting the movement of one element to a closelyspaced adjacent element comprising placing a substantially dielectricliquid mixture between said elements thence placing said two elements ina. closed electric circuit.

2. A method for translating electrical voltage impulses into mechanicalforce comprising moving a first metallic element in contact with asubstantially dielectric fluid suspension in juxtaposition to a secondelement; and impressing said impulses on said elements to cause thefluid to transmit force from the first element to the second.

3. A method for translating an electrical impulse into a mechanicalforce comprising: rotating a first member in contact with asubstantlally dielectric fluid suspension in relatively closely spaced,parallel relation to a second member; and thence impressing an electricpotential on the two members by closing a circuit therebetween.

4. Means for causing a power driven disc to rotate a second free disccomprising: a dielectric fluid between said discs; a finely dividedsubstance suspended in said fluid; and an electrical circuit includingthe two discs, said circuit being broken by the dielectric fluid betweensaid discs.

5. An electro-fluid clutch device comprising: a power drive shaft; adriven shaft in axial alignment with said drive shaft; a drive disc onsaid power shaft; a driven disc on said driven shaft; 9. fluidreceptacle about said discs; a dielectric fluid mixture in saidreceptacle, said mixture entering between said discs, said discs beingelectrically insulated from each other; an electrical control circuitincluding said discs and the dielectric fluid mixture therebetween; andmeans for closing said circuit to impress a voltage upon said discs.

6. An electro-fiuid clutch device comprising: a power drive shaft; adriven shaft in axial alignment with said drive shaft; a drive disc onsaid power shaft; a driven disc on said driven shaft, said discs beingelectrically insulated from each other; a substantially dielectric fluidmixture; means for maintaining said mixture between said discs; andmeans for impressing an electrical potential on said discs to cause thefluid mixture to act as a coupling between the discs to transmit therotation of the first disc to the second disc.

'7. An electro-fluid relay comprising: a fluid cup; a first disc in saidcup; means for rotating said first disc; a second disc in said cup inclose proximity to said first disc and electrically insulated therefrom;a dielectric fluid mixture in said cup; and means for impressing anelectric potential on said discs in response to the closing of a controlcircuit.

8. An electro-fiuid relay comprising: a fluid cup; a first disc in saidcup; means for rotating said first disc; a second disc in said cup inclose proximity to said first disc and electrically insulated therefrom;a dielectric fluid mixture in said cup; a shaft extending from saidsecond disc; a relay arm carried by said shaft; a contact positioned tobe closed by said relay arm; a spring for swinging said arm in onedirection; and means for impressin an electrical potential on said discsto cause a clutching efiect in the fluid between the discs to swing thearm in the other direction.

9. An electro-fluid relay comprising: a fluid cup; a first disc in saidcup; means for rotating said first disc; a second disc in said cup inclose proximity to said first disc and electrically insulated therefrom;a dielectric fluid mixture in said cup; a shaft extending from saidsecond disc; a relay arm carried by said shaft; a. contact positioned tobe closed by said relay arm; a spring for swinging said arm in onedirection; a control circuit including said discs; and means for closingsaid latter circuit to impress an electrical potential on said discs tocause said fluid to exert a clutching effect between the rotating discand the second disc to swing the relay arm in the other direction.

10. An electro-fluid relay comprising: a fluid cup; a first disc in saidcup; means for rotating said first disc; a second disc in said cup inclose proximity to said first disc and electrically inlsulatedtherefrom; a dielectric fluid mixture in said cup; a shaft extendingfrom said second disc: a relay arm carried by said shaft; a contactpositioned to be closed by said relay arm; a spring for swinging saidarm in one direction; a control circuit includin said discs; and aphoto-electric cell in said circuit for passing 9. current in the latterat desired times for energizing the fluid between the plates to exert aclutching efiect with the rotating disc to swing the relay arm in theother direction.

11. An electro-fluid relay comprising: a supporting member; an electricmotor carried by said member; a fluid cup rotatably mounted on saidmember; means for rotating said cup from said motor; a super-imposedplurality of annular discs secured in said cup; an axial shaftjournalled in and projecting from said cup; a plurality of circulardiscs secured to said shaft, there being one circular disc positionedbetween each pair of annular discs; means for electrically insulatingsaid shaft from said cup; a dielectric fluid mixture in said cup; arelay arm secured to and projecting from said shaft: a contact member ateach extremity of movement ofrsaid arm; a spring urging said arm towardone of said contact members; and means for impressing an electricpotential on said annular and circular discs to energize the fluidmixture to exert a gripping action between the two types of discs sothat the rotation of said cup will be imparted to said arm to swing thelatter against the other contact member.

12. An electro-fiuid relay comprising: a supporting member; an electricmotor carried by said member; a fluid cup rotatably mounted on saidmember; means for rotating said cup from said motor; a super-imposedplurality of annular discs secured in said cup; an axial shaftjournalled in and projecting from said cup; a plurality of circulardiscs secured to said shaft, there being one circular disc positionedbetween each pair of annular discs; means for electrically insulatingsaid shaft from said cup; a dielectric fluid mixture in said cup; arelay arm secured to and projecting from said shaft; a contact member ateach extremity of movement of said arm; a spring urging said arm towardone of said contact members; a control circuit including said discs; anda photoelectric cell in said control circuit for passing a current tosaid discs at predetermined times to energize the fluid into exerting agripping action between the two types of discs to cause the rotativemovement of said cup to swing the arm into contact with the othercontact member.

13. Means for transmitting force between two closely spaced independentelements in consequence of an electric voltage impressed on saidelements comprising a dielectric liquid positioned between said elementsand particles of foreign material suspended in said liquid so that theparticles will be affected by said voltage to cause said elements totend to move in unison while under the influence of said voltage,whereby the liquid will act as a coupling between the elements, andmeans for placing said elements in an electrical field.

14. A method for translating an electrical impulse into a mechanicalmovement comprising: moving a first element in a substantiallydielectric fluid mixture in closely spaced relation to a second freeelement therein; and thence impress ing an electric potential on the twoelements by closing a circuit therebetween.

15. The method of controlling the transmission of mechanical forcethrough a homogeneous viscous dielectric fluid suspension which includesthe step of increasing shear stresses transmitted in the fluid byapplying an electric field in a direction at right angles to thedirection of shear.

16. A clutch comprising a pair of spaced metallic walls mountedforrelative movement, a substantially dielectric fluid suspensionbetween said walls characterized by an increased viscosity whensubjected to an electric field, an electric circuit including said wallsfor applying a difference of potential therebetween, and a conditionresponsive device in control of said circuit,

1'7. A clutch comprising a pair of spaced metallic walls mounted forrelative movement; a homogeneous dielectric fluid suspension bridgingthe space between said walls, said fluid suspension characterized by anelectrically alterable viscosity at constant temperature; an electriccircuit including said walls for applying a difference of potentialtherebetween, and a condition responsive device in control of saidcircuit.

18. A method for transmitting motion from one rotatable member toanother rotatable member, comprising placing a substantially dielectricliquid mixture between the members to act as a coupling therebetween andplacing said members in an energized electric circuit.

19. A method of translating electrical impulses into mechanical movementcomprising rotating a member that is arranged in juxtaposition to anormally non-rotating second member, with a substantially dielectricliquid mixture interposed between the members, and impressing electricalimpulses on the members to cause the liquid mixture to act as a couplingbetween the members and transmit motion from the first mentioned memberto the second mentioned member.

20. Means for causing a rotatable member to drive another rotatablemember arranged in closely spaced parallel relation to the firstmentioned rotatable member, comprising a substantially dielectric liquidhaving a finely divided substance suspended therein and arranged betweenthe members, and means for electrically increasing the viscosity of theliquid and the substance suspended therein whereby the latter will actas a coupling between the rotatable members.

21. A coupling for two rotatable members comprising a substantiallydielectric liquid containing a finely divided substance suspendedtherein, said mixture being normally incapable of operatively connectingthe members together, and means for electrically increasing theviscosity of the mixture to cause the same to operatively con nect onemember to the other member.

,22. The method of instantaneously increasing the viscosity of a forcetransmitting fluid composed of a dielectric liquid and a finely dividedsubstance suspended therein; which consists in applying an electricfield to the fluid.

WILLIS M. WINSLOW.

REFERENCES CITED The. following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 735,621 Thomson Aug. 4, 19031,974,483 Brown Sept. 25, 1934 913,541 Mysekin Feb. 23, 1909 (Otherreferences on following page) Number Meissner July 7, 1936 Number Number10 348,641

Name Date Russell Aug. 22, 1939 Severy Feb. 29, 1916 Tolentini Aug. 26,1919 Swanberg Dec. 18, 1928 Rudquist Nov. 3, 1931 FOREIGN PATENTSCountry Date British Nov. 10, 1930 OTHER REFERENCES Elements of StaticElectricity, Atkinson, p ge 2. Published by W. J. Johnston, New York,1887.

Klemgard, Lubricating Greases (1937) pp. 692,

